5.5

CVE-2021-4235: Denial of service in gopkg.in/yaml.v2

Modified
AliasesUBUNTU-CVE-2021-4235DEBIAN-CVE-2021-4235CGA-53g5-qgvr-h4v4
Published 27-12-2022Last modified 11-04-2025

Vulnerability summary

CVE-2021-4235 is a medium (CVSS 5.5) vulnerability in gopkg.in/yaml.v2. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 37% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.43%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 3 · Related 4
DLA-3479-1RHSA-2022:7398USN-6287-1CGA-8CFW-G9M8-H5Q8CGA-P836-MCW8-43J4

Timeline

  1. 27-12-2022
    PublishedVulnerability first disclosed.
  2. 11-04-2025
    Last modifiedVulnerability information updated.

Description

Due to unbounded alias chasing, a maliciously crafted YAML file can cause the system to consume significant system resources. If parsing user input, this may be used as a denial of service vector.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.43%

Chance of exploitation in the next 30 days

Percentile

37%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.41% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Yaml

    Maturity: poc

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard4 products
  • dex-k8s-authenticator< 1.4.0-r34
  • k3d< 5.6.0-r11
  • k3d-proxy< 5.6.0-r11
  • k3d-tools< 5.6.0-r11
Ubuntu4 products
  • golang-github-coreos-discovery-etcd-ioAll versions (No fix recorded)
  • golang-yaml.v2< 0.0+git20160301.0.a83829b-1ubuntu0.1~esm1 | < 0.0+git20170407.0.cd8b52f-1ubuntu2+esm1 | < 2.2.2-1ubuntu0.1
  • singularity-containerAll versions (No fix recorded)
  • webhookAll versions (No fix recorded)
Wolfi3 products
  • k3d< 5.6.0-r11
  • k3d-proxy< 5.6.0-r11
  • k3d-tools< 5.6.0-r11
Debian1 product
  • golang-yaml.v2< 2.2.8-1
Github.com/go-yaml1 product
  • yaml≤ 2.1.0 | All versions (No fix recorded)
Gopkg.in1 product
  • yaml.v2< 2.2.3
Gopkg.in/yaml.v21 product
Yaml_project1 product

8 vendors · 16 products

References

10 links